The present invention relates generally to chemical warfare agent sensors and, more particularly, to a ram-air sample collection device for a chemical warfare agent sensor.
Chemical warfare agent point sensors, such as surface acoustic wave sensors and ion mobility spectrometers, are simply too heavy and large for use on many of the small unmanned aerial vehicles (UAV""s). This is because these sensors all presently require a pump, such as a cyclone or rotary fan/blower to sample the air for agents. The blower/fan is by far the heaviest and largest part of the sensing apparatus.
Thus, current chemical sensors use active pumping to force gas to flow over the sensor element. Pumping is the major source of energy consumption in the devices. Using a ram-air approach, it is possible to force a sample stream to flow over a preconcentrator and sensor device using only the static pressure developed by the relative motion of an air stream to the sensor body. This system can be used in small unmanned aerial vehicles where low power consumption is required, or in other applications where air flows over a vehicle or through a duct.
What is needed, then, is a ram-air collector device that can be mounted to a chemical warfare agent sensor, and make use of the forward momentum of the UAV to force air to be sampled and tested through the sensor module.
The present invention broadly comprises a ram-air collector for a chemical warfare agent sensor, comprising a housing operatively arranged to mount atop the sensor, the housing including a multi-stage channel having an inlet and an outlet, the channel having a first stage having a first height and width proximate the inlet, a second stage having a second lower height and width proximate the micro-fabricated sample preconcentrator, a third stage having a still lower third height and width proximate the surface acoustic wave array detector, and a fourth stage having a fourth height and width proximate the outlet, where the fourth height and width are substantially the same as the first height and width.
The general object of the present invention is to provide a lightweight, efficient ram-air collector, operatively arranged to be mounted to a moving object or vehicle, for a chemical warfare agent or explosives sensor that eliminates the need for a blower or fan to actively pump air over the sensor.